Abstract

Mice often produce ultrasonicvocalizations (USVs) that sweep upwards in frequency from around 60 kHz to around 80 kHz, and similarly sweep downwards in frequency from 80 kHz to 60 kHz. Whether or not these USVs are used for communication purposes is still unknown. Determining the ability of mice to discriminate between synthetic upsweep and downsweep frequency-modulated stimuli will expand the current knowledge about acoustic communication in mice. Mice were trained and tested using operant conditioning procedures and positive reinforcement to discriminate between upsweeps and downsweeps. The stimuli varied in bandwidth, duration, and direction of the sweep. The animals responded when they heard a change in the repeating background, indicating that they could discriminate background from target. The mice performed significantly worse discriminating between background and targets when the stimuli occupied the same bandwidths. Further, the mice’s discrimination performance became much worse when the duration approached that of their natural vocalizations. When the sweeps occupied different frequency ranges and longer durations, discrimination performance improved. These results collected using artificial stimuli created to mimic natural USVs indicate that the bandwidth of vocalizations may be much more important for communication than the frequency contours of the vocalizations. [Work supported by NIH DC012302.]